1. Field of the Invention
The present invention relates to a method and device for cooling an object to be processed to a target temperature.
2. Description of the Related Art
In general, in the processing steps for, e.g., a semiconductor substrate, a glass substrate, or the like, a series of processes in which a circuit pattern or the like is reduced and transferred to a photoresist on the substrate by using a photolithography technique, and the resultant photoresist is developed are performed. In such processes, the substrate is washed and then heated to completely remove moisture from the substrate surface. After the heating, the heated substrate is quickly cooled to an atmospheric temperature to shorten the manufacturing time. As a cooling device for this purpose, a device disclosed in Japanese Examined Utility Model Publication No. 6-2262 is known.
In conventional cooling device, as indicated by a curve a in FIG. 12, even if control is performed using a coolant kept at a target temperature to cool the substrate having a high temperature K1 to a target temperature K2, a considerably long time (T3) is disadvantageously required to cool the substrate to the target temperature after the temperature of the substrate is close to the target temperature K2. In FIG. 12, the ordinate indicates the temperature (.degree. C.) of the substrate, and the abscissa indicates a time (second). In an example, the temperature K1 is about 130.degree. C., the temperature K2 is about 23.degree. C., and the time T3 is about 60 seconds.
In addition, in the photolithography step described above, the cooling step must be performed for one substrate several times. For this reason, in order to increase a throughput, one important problem is to shorten a time for the cooling process.